U.S. Pat. Nos. 3,156,720 and 3,224,972 disclose as antioxidants 4,4'-thiobis(2,6-dialkylanilines). These patents describe several 3,5-dialkyl-4-aminobenzenethiols, but not any of the instant compounds derived therefrom.
U.S. Pat. Nos. 3,934,972 and 3,953,162 mention unsubstituted 4-aminophenylthiosuccinic acid as a dye fixation agent. There is no mention of corresponding dialkyl or diaralkyl substituted compounds nor of the use of the unsubstituted succinic acids as stabilizers.
Belgian Patent No. 625,216 (=Chem. Abst. 60, 10600) discloses unsubstituted S-(4-aminophenyl)thiophosphorus acid esters as parasiticides. Again no mention of an stabilization efficacy for such esters is made.